The nature, properties and path of secretion of collagen precursors, procollagens, synthesized by different connective tissue cells in culture is being probed in order to determine the exact sequence of events in collagen synthesis, modification and secretion. Many heritable and acquired connective tissue disorders are related to an inability to complete the collagen synthetic and maturation pathway. Thus, we hope by studying cells in culture which are altered in these processes to be able to relate specific aberrations to diseases processes.